PT11 Exposure to POPs Through Terrestrial Vegetation
Exhibit Hall
8:00 AM - Tuesday
(PT141) Comparison of perchlorate exposure via food and water in deer mice.
Severt, S1, Isanhart, J1, Jackson, W1, Anderson, T1, Smith, P1, 1 Texas Tech University, Lubbock, TX, United States
ABSTRACT- Perchlorate contamination in the environment has raised considerable concern in recent years. Contaminated water may be used for drinking or irrigation of crops intended for use by humans and livestock. Plants may accumulate perchlorate at higher concentrations than that of the surrounding soil and water, suggesting an additional source of exposure. Perchlorate interferes with the production of thyroid hormones, thyroxine (T4) and triiodothyronine (T3), by competing with iodide for uptake into the thyroid gland. Due to the solubility of perchlorate, previous small mammal studies have used water as the dosing vehicle. To date, there is no published research on the potential effects of perchlorate contaminated food. We conducted a two-generation study comparing the effects of perchlorate in deer mice exposed via contaminated food to those exposed via water. Perchlorate contaminated soybean plants (Glycine max) were incorporated into rodent diet and fed to mice ad libidum. The second group was exposed to perchlorate in water at a concentration approximately equal to that of the food exposed group. There were no significantly different histopathological measurements between groups. There were no differences in the number of uterine placental scars between treatment groups. Analysis of thyroid glands for T4 content showed no significant differences between treatments. After 21 days, males in the perchlorate contaminated food group (PCF) had decreased T3 concentrations compared to controls. At day 44, males in the PCF treatment had elevated concentrations of T4 compared to controls. Animals in the perchlorate contaminated water (PCW) group following gestational, lactational, and post-lactational exposure had elevated T3 concentrations compared to controls. We were unable to detect perchlorate related toxicity among deer mice administered doses of approximately 1 mg/kg/day via water or food.
Key words: thyroid, perchlorate, thyroid hormone, deer mouse